This thesis explores the discourses underpinning therapists’ and non-therapists’ constructions of sexual experimentation and masturbation in heterosexual relationships. A constructionist thematic analysis of 200 story completions written by 58 therapists and 53 non-therapists showed that discursive imperatives to do ‘normal’ gender coalesce in participants’ accounts of heterosex to perpetuate prescriptive notions of sexual practice, produce unequal gendered relationships and generate different obligations and entitlements for women and men. Whilst both therapists and non-therapists drew on the same problematic heteronormative discourses to construct masturbation and sexual experimentation, the ‘difficulties' that these caused in relationships were generally framed by therapist’s as opportunities for personal growth and for increasing emotional depth within relationships. It is suggested that therapists’ understanding of relationships and intimacy may be informed by their therapeutic training and their overreliance on narrow and restrictive discourses of heterosex may to point towards a gap in critical training in sexual issues. The findings are situated within a wider discussion of counselling psychology’s role in addressing heteronormativity in psychological practice. It is argued that counselling psychology’s origins as an alternative to mainstream approaches and its stated aim of pursuing a wider social justice agenda positions it as a potential bridge between critical approaches and applied psychology. This research concludes that fostering a critical stance in counselling psychologists will not only allow the social justice agenda of the discipline to be met more consistently but could also support a more coherent and consistent professional identity. Key words: Counselling Psychology, coital imperative, heteronormativity, masturbation, sex therapy, sexual experimentation, thematic analysis, therapeutic training.